SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '389638a01cbc32fe04f363c4b01ea15968d68d9145f4235d92193475453b1863' 
  AND token = 'KyCbyQ670bSGgif0w6akY5UUJV6twjnffxWSGEwbGic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}